1. Field of the Invention
The present invention relates to an image sending/receiving device for registering a set of resolutions with which an image reproducing device can output reproduced image, based on a set of resolutions read out from an image display device and another set of resolutions pre-stored in the image sending/receiving device.
2. Description of the Related Art
FIG. 6A shows a conventional system in which a DVD player, an AV amplifier and a display device, all conforming to the HDMI (High Definition Multimedia Interface) standard, are connected together via HDMI cables. The image data reproduced by the DVD player is output to the display device via the AV amplifier.
The display device can use different display resolutions, and EDID (Extended Display Identification Data) specifying a set of resolutions (e.g., “XGA”, etc.) compatible with the display device is stored in a PROM (not shown) provided in the display device (Japanese Laid-Open Patent Publication No. 11-15425).
The AV amplifier also includes ROM therein storing a set of resolutions (which are all in conformity with the HDMI standard). The AV amplifier reads out the EDID from the display device to which it is connected, and identifies resolutions compatible with the display device from the EDID. The AV amplifier produces and registers new EDID in a PROM (not shown), wherein the new EDID specifies a subset of resolutions among those pre-stored in the ROM of the AV amplifier that are also included in the set of resolutions read out from the display device.
The DVD player reads out the EDID from the PROM of the AV amplifier to determine a set of resolutions that are available both to the AV amplifier and to the display device. The resolution of images to be output from the DVD player to the AV amplifier is specified by a user's operation based on the set of available resolutions. Specifically, the DVD player displays a resolution setting screen with a plurality of resolutions, and the user selects one of the resolutions. The resolutions displayed on the resolution setting screen are a set of resolutions that are included both in the resolutions pre-stored in the DVD player and in the resolutions read out from the PROM of the AV amplifier. Thus, it is possible to display on the resolution setting screen a set of resolutions that are available both to the AV amplifier and to the display device.
FIG. 6B shows a similar conventional system in which an AV amplifier is connected to a display device conforming to the DVI (Digital Visual Interface) standard (which is compatible with the HDMI standard) via a DVI cable. The AV amplifier reads out EDID from the display device, and the AV amplifier produces and registers new EDID in the PROM, the new EDID specifying a subset of resolutions among those pre-stored in the ROM of the AV amplifier that are also included in the set of resolutions specified by the EDID of the display device. The DVD player reads out the EDID from the PROM of the AV amplifier, and displays the set of resolutions included in the set of resolutions specified by the EDID on the resolution setting screen.
As described above, stored in the PROM of the AV amplifier is a set of resolutions that are stored both in the ROM of the AV amplifier and in the PROM of the display device. Therefore, a resolution that is compatible with the display device but is not stored in the ROM of the AV amplifier is not displayed on the resolution setting screen of the DVD player, and the DVD player cannot output image data in that resolution. This problem is common in cases where a display device of the DVI standard is connected to an AV amplifier of the HDMI standard. A display device of the DVI standard has a greater variety of resolutions than that of the HDMI standard.
For example, assume that the ROM of the AV amplifier stores resolutions a, b, c and d, and the PROM of the display device stores resolutions a, b, c, d, e and f. Then, only the common resolutions a, b, c and d are registered in the PROM of the AV amplifier, and the resolutions e and f are not registered. As a result, only the resolutions a, b, c and d are displayed on the resolution setting screen of the DVD player, and the resolutions e and f are not displayed therein. Therefore, it is not possible to select e or f as the resolution in which the DVD player outputs image data. Thus, even though the display device is capable of displaying images in the resolutions e and f, the DVD player cannot output image data in the resolutions e and f.
In the HDMI standard, an HDMI-sync display device is required to have all the available resolutions accurately pre-stored in the PROM in the display device. Therefore, when the DVD player displays the resolution setting screen based on the EDID read out by the AV amplifier from the display device, a set of resolutions compatible with the display device are accurately displayed on the resolution setting screen, and the user can select one of the resolutions compatible with the display device.
In the DVI standard, however, a display device is not required to have all the available resolutions accurately stored in the PROM. Therefore, a display device conforming to the DVI standard may have only some or none of the available resolutions stored in the PROM, due to PROM capacity limitations. Specifically, there may be one or more resolutions that are compatible with the display device but are not stored in the PROM. When such a display device is connected to an AV amplifier, the DVD player will display the resolution setting screen based on the EDID of the display device. Then, the resolutions compatible with the display device will not accurately be displayed on the resolution setting screen. As a result, there will be some resolutions that are compatible with the display device but cannot be selected as resolutions in which the DVD player outputs image data, whereby the DVD player cannot output image data in such resolutions.